macvlan: remove one synchronize_rcu() call
When one macvlan device is dismantled, we can avoid one
synchronize_rcu() call done after deletion from hash list, since caller
will perform a synchronize_net() call after its ndo_stop() call.
Add a new netdev->dismantle field to signal this dismantle intent.
Reduces RTNL hold time.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Patrick McHardy <kaber@trash.net>
CC: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index d7c0bc62..07bcb80 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -70,16 +70,17 @@
hlist_add_head_rcu(&vlan->hlist, &port->vlan_hash[addr[5]]);
}
-static void macvlan_hash_del(struct macvlan_dev *vlan)
+static void macvlan_hash_del(struct macvlan_dev *vlan, bool sync)
{
hlist_del_rcu(&vlan->hlist);
- synchronize_rcu();
+ if (sync)
+ synchronize_rcu();
}
static void macvlan_hash_change_addr(struct macvlan_dev *vlan,
const unsigned char *addr)
{
- macvlan_hash_del(vlan);
+ macvlan_hash_del(vlan, true);
/* Now that we are unhashed it is safe to change the device
* address without confusing packet delivery.
*/
@@ -345,7 +346,7 @@
dev_uc_del(lowerdev, dev->dev_addr);
hash_del:
- macvlan_hash_del(vlan);
+ macvlan_hash_del(vlan, !dev->dismantle);
return 0;
}
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index a134d80..ca333e7 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -1293,7 +1293,9 @@
NETREG_UNREGISTERED, /* completed unregister todo */
NETREG_RELEASED, /* called free_netdev */
NETREG_DUMMY, /* dummy device for NAPI poll */
- } reg_state:16;
+ } reg_state:8;
+
+ bool dismantle; /* device is going do be freed */
enum {
RTNL_LINK_INITIALIZED,
diff --git a/net/core/dev.c b/net/core/dev.c
index 155de20..d945379 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5126,7 +5126,7 @@
list_del(&dev->unreg_list);
continue;
}
-
+ dev->dismantle = true;
BUG_ON(dev->reg_state != NETREG_REGISTERED);
}